Linearly Scale Light Temperature
You can map color temperature like you can map any other shader value with nodes, no need to involve drivers unless required.



Just use either direct texture coordinates as input for a Color Mix node, or use World Coordinates from a Geometry node instead.

Separate the desired direction, use math nodes to adjust length of progression, then feed it into a Color Mix with each temperature plugged to a Color socket.



Alternatively for more complex progression patterns you may use a gradient texture.